Vacuum cleaners, for example domestic vacuum cleaners, typically comprise a main body, a vacuum generator for drawing an airflow into the main body and a cleaner head, or a floor tool attached to a hose, through which dirty air is drawn.
In order to assist cleaning, the cleaner head or floor tool is often provided with an agitator, such as a motor-driven brush bar or rotary heads. The agitator dislodges dirt from a surface to be cleaned, for example from between the fibres of carpets, so that the dirt can be more readily entrained by the airflow into the main body of the vacuum cleaner.
When the vacuum cleaner is used to clean delicate surfaces, for example polished wooden or tiled surfaces, or delicate fabrics, the agitator can scour and damage the surface, which is undesirable.
In order to solve this problem, vacuum cleaners are often provided with an agitator switch which allows the agitator to be turned off independently of the vacuum generator.
However, it has been found that, if the agitator has been turned off, a user will often forget to turn the agitator back on again when next operating the vacuum cleaner. A user will therefore often use the vacuum cleaner to clean carpets with the agitator being unknowingly switched off.
Known vacuum cleaners couple the agitator switch with the vacuum generator switch so that actuation of the vacuum generator automatically actuates the agitator. The agitator is then turned off each time by the user if not required. This ensures that the user cannot forget to turn the agitator on when using the vacuum cleaner.
In order to allow the agitator to be switched off independently of the vacuum generator, and to ensure correct sequencing resumes when the vacuum cleaner is switched off and on regardless of the whether the agitator has been turned off or on, switching of the agitator and the vacuum generator must be coupled or uncoupled accordingly.
A known switching mechanism is configured so that when both an agitator switch and a vacuum generator switch are open (i.e. the agitator and the vacuum generator are switched off), both switches are coupled together. Closing the vacuum generator switch therefore automatically closes the agitator switch. The switching mechanism is further configured such that the agitator switch is decoupled from the vacuum generator switch by closing the vacuum generator switch. The vacuum generator switch and the agitator switch can then be operated independently of each other.
In addition, each time the agitator switch is opened (i.e. the agitator is turned off), the agitator switch is re-coupled with the vacuum generator switch. This ensures that subsequent closing of the vacuum generator switch causes the agitator to be switched on with the vacuum generator switch. Consequently, in all cases, the agitator switch is coupled with the vacuum generator switch prior to turning the vacuum generator on. This ensures that the user cannot forget to turn the agitator on when using the vacuum cleaner.
A problem associated with the known switching mechanism is that coupling of the agitator switch with the vacuum generator switch whilst the vacuum generator switch is closed (i.e. the vacuum generator is on) causes the agitator to be activated briefly as the vacuum cleaner is switched off. Although the vacuum generator switch also acts as a master switch which turns the agitator off, the user, who until this point has been operating the vacuum cleaner with the agitator turned off, can find the brief activation of the agitator disconcerting.